Process of producing azo dyestuffs on the fiber



Patented July 7, 1936 UNITED STATES PATENT OFFICE 2,046,425 rnoonss 0FPRODUCING AZO nrns'rurrs ON THE FIBER.

tion of Delaware No Drawing.

Application September 15, 1932,

Serial No. 633,376. In Great Britain September 25, 1931 3 Claims.

The present invention relates to a process of producing azo-dyestuffson. the fiber, more particularly it relates to improvements in threingfibers, yarns and fabrics with azo-dyestufis.

In the usual method'of producing azo-dyestufis on the fiber, thematerial is impregnated with a solution ofthe substantive couplingcomponent or passive component", such as an arylide of2.3-hydroxynaphthoic acid, acetoacetic acid, 2-

hydroxyanthracene-3-carboxylic. acid, ortho-hyweight, takes place ratherslowly and incomplete-. When using inly under the usual conditions. theusual method a diazo-compound which couples slowly it can be observedthat, due to the incomplete coupling, in the after-treatment of thedyeings, particularly in the soap bath, part of the diazo-compound whichhas noteoupled is dissolved from the material.

Most diazonium salts are somewhat unstable except at very lowtemperatures. Some of the passive components also, such as the alkalimetal salts of 2.3hydroxynaphthoic acid arylamides, commonly known underthe name naphtholates, are not wholly stable under the conditions ofcoupling. Therefore, if the time of coupling is unduly prolonged,decomposition may take place with the production of undesiredby-products.

The disadvantage is particularly annoying in the production of resistarticles: The-unchanged diazo-compound which comes oil in the soap bath,often reacts with the coupling component present on those parts of thematerial where the resists (white or. colored resists) were applied,thus staining or coloring. the reserved parts.

We have now found that the rate of coupling is greatly accelerated byincrease in temperature and that notwithstanding the higher degree'ofinstability exhibited by the reagents, such as the diazonium salt, atthese higher temperatures, improved results, such as much morecompletely coupled and darker dyeings, may be obtained by performing thecoupling at elevated temperatures. It is necessary, of course, that thediazonium salt and the passive components shall be in intimate contactin the correct proportions for reaction when the temperature is raisedto accelerate the coupling. The process according to the presentinvention, therefore, consists in impregnating the goods with a passivecomponent and with a solution of a diazonium salt in thecorrectproportions for coupling and then raising the temperature rapidlyto a value substantially above atmospheric temperature. The accelerationof the coupling is progressive with rise of temperature but, generallyspeaking, temperatures above 50 C. and preferably round about to C. aredesirable. Preferably, the impregnation is performed at a sufiicientlylow temperature to retard decomposition of the reagents.

The goods are most suitably impregnated with the passive component, suchas an arylide of 2.3- hydroxynaphthoic acid or other suitablesubstantive coupling component, passed through a diazonium solution andthen subjected to a heating operation. Thus they may, immediately afterthe impregnation, be dried by passing them over drying tins. Such methodof drying involves heating very rapidly to temperatures round about 100C. and under these circumstances the coupling takes place in time of theorder of a few seconds.

Or the material after impregnation with the coupling component andtreatment with the diazo solution is immediately passed through a heatedspace, for instance, through a steamer or through the space betweenheated plates.

The dyeings obtained by operating in accordance with the presentinvention are usually darker, in some cases they are 30 to 40 per centstronger, than those obtained by the known processes, probably owing tothe smaller amount of decomposition of thecomponents. There is less riskof injury to the goods from soiling by decomposition products. 4

An important advantage of the present inven tion is that mixtures ofdifferent diazonium salts and salts which are ordinarily too slow incoupling to be dyed continuously or are not. sumciently soluble, may beutilized" satisfactorily, by operating according to the method of thepresent invention.

The process of the present invention also is of advantage in theproduction of resist efiects, since a considerable amount of organicacid may be employed in the diazonium solution without injuriouslyaffecting the coupling processes.

For performing the coupling at elevated temperatures there may be usedthe usual drying tins or other suitably heated cylinders.

If instead drying over tins it is preferred to use a steaming apparatus,there may be used the usual construction, for instance, an apparatusprovided with perforated steam-pipes and with guide rollers for thematerial. Another modification of carrying out the coupling at elevatedtemperatures is the use of heated plates, for instance, of flat hollowplates of iron or other metal, electrically heated plates or othersuitably shaped heating devices. The-heating plates are arranged inpairs facing each other at a suitable distance apart, so that there is aheated space between them through which the material is conducted.

Such use of heating plates is of advantage, for instance, in theproduction of resist articles. It is easily possible to arrange theheating plates and the guide rollers for thematerial in such a mannerthat the material, on its way from the diazo bath to the washingmachine, is in contact with rollers only on its reverse (unprinted)side. This avoids removal of the printed resists from the material, asis possible, for example, if the printed side of the material is incontact with the rollers.

' The new process may advantageously be ap- 'plied to the production ofdyeings on the fiber in the case of all slowly coupling diazo-compounds.Slowly coupling diazo-compounds are, for instance, those of bases of thegeneral formula:

wherein R1 means a substituted or unsubstituted aromatic radical and R2a substituted or unsubstituted iso-cycli'c radical.

= An exhaustive description of all possible slow- .iy couplingdiazo-compounds is not necessary,

subjected .to a heating operation. The inven-' tion is not limited to aparticular heating device. Instead of drying tins, steaming apparatus orheated plates or any other suitable construction may be used. I

The following examples serve to illustrate the invention, but they arenot intended to limit it thereto:

-' (1) A fabric of cotton impregnated with 1% of2".3-hydroxy-naphthoyl-aniline in the usual manner is padded in adiazo-solution containmg:

3% of diazonium chloride of 4;amino-4'-methoxy-diphenylam'ine,

5% of Epsom salt (magnesium sulfate),

- 1% of formic acid, dried over tins and soaped. a

(2) A fabric prepared in 2%%2'.3'-hydroxynaphthoyl-2.5-dimethoxy-l-aminobenzene in the usual manneris passed through a suspension of 7% of zinc chloride double salt of thediazo compound of a-amino-anthraquin'one,

/z% of tragacanth, 1

1% of acetic acid, dried over heated cylinders and soaped.

- (3) Upon a fabric prepared in 2%2'.3'-hydroxynaphthoyl-4-chloroaniline in the usual manner, is printed aresist consisting of 20 parts by wei ht of sodium sulfoxvlate,

parts by weight of British gum thickening. The fabric is then paddedthrough a diazo-solution prepared in the usual manner, containing:

2% of 4.4-diaminodiphenylamine,

1% of formic-acid, dried at elevated temperature and washed. A whiteresist is obtained upon a navy ground.

(4) A fabric prepared in 2% of 2'3'-hydroxynaphthoy1-2.5 dimethoxy laminobenzene is padded through the nip in a diazo-solution con- 10taining:

1% of 2.5-dichloroaniline,

0.75% of 4.4'-'diamlnodiphenylamine, and dried at elevated temperature.The goods are soaped in the presence of one-quarter per 15' cent ofcaustic'soda at the boil, when a brown shade is obtained.-

ner by passing the fabric over, drying tins which are steam heated.Preferably the temperature of the tins, or at least of those over whichthe fabric first passes, is just below that which would cause the liquidupon the fabric to dry. The numberof 25 tins and their preferredtemperature is dependent upon the nature and weight of the fabric andthe weight of liquor therein. With a fabric weighing 30 lbs. for 120yards and" taking out 28 lbs. of liquor per piece, 24 tins each of 18inches diame- 30 ter are suitable. All are steam heated, the last 20 atabout 2 or 3 lbsxexcess pressure.

(5) (a) Grounding liquor 12 grams of 2'3-hydroxynaphthoyl-aniline are pmade into a paste with 1 15, cc. of Turkey red oil and 15 cc. of causticsoda solution of 38 136., the

whole is dissolved with boiling water and made. up with water to w 40 1liter Temperature of the grounding bath: 35 C. The material is groundedon a foulard and dried in the hotflue.

(1;) Developing bath 27 grams of diazonium chloride of -amino- 4'methoxy diphenylamine are made up with of cold water to 1 literTemperature of the developing, bath: 15 C. to :55 20 C. The grounded anddried material is developed on a two-roller-foulard andimmediately-without exposureto air-passed through a steamer. Thesteaming temperature is about C. to C. and the time of steaming about 6030-seconds. Thereupon, the material is passed through a bath at 40 C.containing 5 cc. of hydrochloric acid of 20 per liter, rinsed andsoaped-at boiiingteniperature.

(6) The material which has been grounded and 35- dried as indicated inExample 5 is printed with the following white resist:

250 grams of aluminium sulfate 1:1 500 grams of starch tragacanththickening, 100 grams of kaolin powder,

grams of water.

Instead of using a steamer, the material may be passed through the spacebetween heated plates arranged in pairs facing each other at a suitabledistance apart, for instance, fiat hollow iron plates heated by means ofsteam. Thereupon, the goods are passed through a bath at 80 0.,containing 30 cc. of hydrochloric acid of 20 B. per liter, rinsed incold water, passed through a bisulfite bath of 80 C. containing 15 cc.of sodium bisulfite solution of 38 B. per liter, rinsed and soaped. Awhite resist is obtained upon a blue ground.

(7) Grounding liquor: as indicated in Example 5.

Yellow resist 80 grams '70 grams 205 grams 400 grams grams 10 grams 120grams paste 50 grams 1000 grams Development and further treatment asindicated in Example 6. A yellow resist is obtained upon a blue ground.

(8) Grounding liquor: as indicated in Example 5.

Green resist grams of the sulfuric acid ester salt of the leuco compoundof dimethoxydibenzanthrone,

Development and further treatment as indicated in Example 6. A greenresist is obtained upon a blue ground.

We claim:

1. In the process of producing azo-dyestufis on the fiber byimpregnating the material with a s0- vlution of a substantiveazo-component and subsequent developing in a solution of a slowlycoupling diazo-compound, the step which comprises subjecting thematerial, immediately after the treatment with the diazo bath, to adry-heating operation at a temperature of about C. to about C.

2. In the process of producing azo-dyestufis on r the fiber byimpregnating the material with a solution of a substantive azo-componentand subsequent developing in a solution of a slowly couplingdiazo-compond, the step which comprises subjecting the material,immediately after the treatment with the diazo bath, to a steamingoperation.

3. In the process of producing azo-dyestufi's on the fiber byimpregnating the material with a solution of a 2.3-hydroxy-naphthoicacid arylide and subsequent padding in a solution of a diazonium salt ofa base of the general formula:

wherein R1 means a substituted or unsubstituted aromatic radical and R2a substituted or unsubstituted isocyclic radical, in the correctproportions for coupling, the step which comprises subjecting thematerial, immediately after the treat ment with the diazo bath, to arapid heating operation in the neighborhood of 100 C. to 110 C.

CHARLES SCHWABE PARKER. CHARLES LEONARD WALL. FRANKLIN FARRINGTON.

Developing bath 80 grams of a mixture of ethyleneglycol, di- 27 gramsoi! diazonium chloride of 4-aminohydmxy ethylene glycol and 4' methoxydiphenylamine are monomethylether' 1'75 grams of water made up with 973cc of c 01 d water to 400 grams of starch-tragacanth thickening, 80grams of sodium bisulfite of 38 B.,

1 liter 15 grams of ammonium thiocyanate, v 120 grams of chrome yellow,60% paste (neu- The material is developed on a two-roller-foutral leadchromate). lard and immediately passed through a steamer. 50 grams ofkaolin paste 1:1, The steaming temperature is about 110 C. to C. and thetime of steaming about 30 seconds. 1000 grams

